Sevoflurane undergoes degradation in soda lime to produce Compound A. At which carbon dioxide absorbent temperature does this degradation become clinically significant, and what organ is at risk?

• A Above 45°C; liver
• B Above 80°C; brain
• C Above 55°C; lung
• D Above 60°C; kidney ✓

Explanation

Compound A (fluoromethyl-2,2-difluoro-1-[trifluoromethyl]vinyl ether) is produced from sevoflurane reacting with soda lime, particularly at temperatures above 60°C. Animal studies show nephrotoxicity from Compound A, though significant clinical renal toxicity in humans has not been conclusively demonstrated at clinically used concentrations. Using fresh gas flows ≥2 L/min minimises Compound A accumulation. Baralyme generates more Compound A than soda lime at equivalent temperatures.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.